Ceramic electronic component and method of manufacturing the same

ABSTRACT

A ceramic electronic component includes a body including a dielectric layer and an internal electrode, and an external electrode disposed on the body and connected to the internal electrode. The dielectric layer includes a plurality of dielectric grains, and at least one of the plurality of dielectric grains has a core-dual shell structure having a core and a dual shell. The dual shell includes a first shell surrounding at least a portion of the core, and a second shell surrounding at least a portion of the first shell, and a concentration of a rare earth element included in the second shell is more than 1.3 times to less than 3.8 times a concentration of a rare earth element included in the first shell.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims benefit of priority to Korean Patent ApplicationNo. 10-2020-0001979 filed on Jan. 7, 2020 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field

The present disclosure relates to a ceramic electronic component and amethod of manufacturing the same.

2. Description of Related Art

In general, a ceramic electronic component using a ceramic material suchas a capacitor, an inductor, a piezoelectric element, a varistor, athermistor, or the like may include a ceramic body made of the ceramicmaterial, an internal electrode formed in the ceramic body, and anexternal electrode disposed on a surface of the ceramic body to beconnected to the internal electrode.

Multilayer ceramic capacitors (MLCCs), a type of ceramic electroniccomponent, are being developed to have increasing capacity through theultra-thinning of layers thereof.

A high capacity multilayer ceramic capacitor (MLCC) may include bariumtitanate (BaTiO₃) as a main material to form a body, and nickel as abase material of the internal electrode.

Such a body is generally fired in a reduction atmosphere. In this case,the dielectric therein should be resistant to the reduction.

However, due to the inherent characteristics of the oxide, oxygen in theoxide may escape during the firing operation in the reduction atmosphereto generate oxygen vacancies and electrons. Therefore, reliability andinsulation resistance (IR) thereof may be deteriorated.

In order to solve the problems, a method has been proposed in which arare earth element such as Dy, Y, Ho, or the like is added to suppressthe generation of the oxygen vacancies, to reduce mobility of oxygenvacancies, and to remove electrons generated by addition of a transitionmetal.

However, there remains a problem that the above method may be noteffective when layers in the multilayer ceramic capacitor are thinned tohave a relatively high capacity or when a relatively high voltage isused therein under more severe use environments.

In addition, when the rare earth element or the transition element isadded by the above method, a high temperature lifespan characteristicsmay be deteriorated or a temperature coefficient of capacitance (TCC)characteristic, depending on a change in temperature, may bedeteriorated.

SUMMARY

An aspect of the present disclosure is to provide a ceramic electroniccomponent and a method of manufacturing the same, capable of improvingreliability.

An aspect of the present disclosure is to provide a ceramic electroniccomponent and a method of manufacturing the same, capable of improvingthe temperature coefficient of capacitance (TCC) characteristic.

An aspect of the present disclosure is to provide a ceramic electroniccomponent and a method of manufacturing the same, capable of improvinghigh temperature lifespan characteristics.

An aspect of the present disclosure is to provide a ceramic electroniccomponent and a method of manufacturing the same, capable of improving adielectric constant.

However, the objects of the present disclosure are not limited to theabove description, and will be more readily understood in the course ofdescribing specific embodiments of the present disclosure.

According to an aspect of the present disclosure, a ceramic electroniccomponent includes a body including a dielectric layer and an internalelectrode, and an external electrode disposed on the body and connectedto the internal electrode. The dielectric layer includes a plurality ofdielectric grains, and at least one of the plurality of dielectricgrains has a core-dual shell structure having a core and a dual shell.Additionally, the dual shell includes a first shell surrounding at leasta portion of the core, and a second shell surrounding at least a portionof the first shell, and a concentration of a rare earth element includedin the second shell is more than 1.3 times to less than 3.8 times aconcentration of a rare earth element included in the first shell.

According to another aspect of the present disclosure, a method ofmanufacturing a ceramic electronic component includes preparing ceramicgreen sheets each including a base material powder and a minor componentadded to the base material powder, the base material powder having acore-shell structure having a core and a shell, and the shell includinga rare earth element. A conductive paste for an internal electrode isprinted on the ceramic green sheets, and the printed ceramic greensheets are stacked to prepare a stacked body. The stacked body is firedto prepare a body including a dielectric layer and an internalelectrode, and an external electrode is formed on the body. An amount ofthe rare earth element included in the base material powder is more than0.6 times to less than 2.4 times an amount of a rare earth elementincluded in the minor component.

According to another aspect of the present disclosure, a ceramicelectronic component includes a body including first and second internalelectrodes overlapping each other with a dielectric layer disposedtherebetween. In a region of the dielectric layer disposed 0.41 μm orless from both the first and second internal electrodes, 50% or more ofa total number of dielectric grains in the dielectric layer have acore-dual shell structure having a core, a first shell having acomposition different from the core and surrounding at least a portionof the core, and a second shell having a composition different from thefirst shell and surrounding at least a portion of the first shell.

According to another aspect of the present disclosure, a ceramicelectronic component includes a body including first and second internalelectrodes overlapping each other with a dielectric layer disposedtherebetween. In a region of the dielectric layer disposed 0.41 μm orless from both the first and second internal electrodes, dielectricgrains of the dielectric layer have core-shell structures having a coreand a first shell surrounding at least a portion of the core andincluding a rare earth element in a concentration higher than the core.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will be more clearly understood from the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective view schematically illustrating a ceramicelectronic component according to an embodiment of the presentdisclosure.

FIG. 2 is a schematic cross-sectional view taken along line I-I′ of FIG.1 .

FIG. 3 is a schematic cross-sectional view taken along line II-II′ ofFIG. 1 .

FIG. 4 is an exploded perspective view schematically illustrating a bodyin which a dielectric layer and an internal electrode are stacked,according to an embodiment of the present disclosure.

FIG. 5 is an enlarged view of region P of FIG. 2 .

FIG. 6 is a schematic diagram illustrating a grain having a core-dualshell structure.

FIG. 7 illustrates intensities of Dy measured as results of XRF EDS lineanalysis for grains having a core-dual shell structure of the InventiveExample of Test No. 9.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to specific embodiments and the accompanying drawings.However, embodiments of the present disclosure may be modified to havevarious other forms, and the scope of the present disclosure is notlimited to the embodiments described below. Further, embodiments of thepresent disclosure may be provided for a more complete description ofthe present disclosure to the ordinary artisan. Therefore, shapes andsizes of the elements in the drawings may be exaggerated for clarity ofdescription, and the elements denoted by the same reference numerals inthe drawings may be the same elements.

In the drawings, portions not related to the description will be omittedfor clarification of the present disclosure, and a thickness may beenlarged to clearly show layers and regions. Further, throughout thespecification, when an element is referred to as “comprising” or“including” an element, it means that the element may further includeother elements as well, without departing from the description, unlessspecifically stated otherwise.

In the drawings, an X direction may be defined as a second direction, anL direction, or a longitudinal direction; a Y direction may be definedas a third direction, a W direction, or a width direction; and a Zdirection may be defined as a first direction, a stacking direction, a Tdirection, or a thickness direction.

Ceramic Electronic Component

FIG. 1 is a perspective view schematically illustrating a ceramicelectronic component according to an embodiment of the presentdisclosure.

FIG. 2 is a schematic cross-sectional view taken along line I-I′ of FIG.1 .

FIG. 3 is a schematic cross-sectional view taken along line II-II′ ofFIG. 1 .

FIG. 4 is an exploded perspective view schematically illustrating partsof a body in which a dielectric layer and an internal electrode arestacked, according to an embodiment of the present disclosure.

FIG. 5 is an enlarged view of region P of FIG. 2 .

FIG. 6 is a schematic diagram illustrating a grain having a core-dualshell structure.

Hereinafter, a ceramic electronic component 100 according to anembodiment of the present disclosure will be described in detail withreference to FIGS. 1 to 6 . Also, a multilayer ceramic capacitor will bedescribed as an example of a ceramic electronic component, but thepresent disclosure is not limited thereto. In addition, a ceramicelectronic component using a ceramic material such as a capacitor, aninductor, a piezoelectric element, a varistor, a thermistor, or the likemay be also applied.

A ceramic electronic component 100 according to the embodiment of thepresent disclosure includes a body 110 including a dielectric layer 111and an internal electrode 121 or 122; and an external electrode 131 or132 disposed on the body 110 and connected to the internal electrode 121or 122, wherein the dielectric layer 111 includes a plurality ofdielectric grains 10 a, 10 b, and 10 c, wherein at least one of theplurality of dielectric grains has a core-dual shell structure having acore C and a dual shell, wherein the dual shell includes a first shellS1 surrounding at least a portion of the core C, and a second shell S2surrounding at least a portion of the first shell S1, wherein aconcentration of a rare earth element included in the second shell S2 ismore than 1.3 times to less than 3.8 times a concentration of a rareearth element included in the first shell S1.

In the body 110, a plurality of dielectric layers 111 may be alternatelystacked with the internal electrode 121 or 122. Additionally, theinternal electrode 121 and 122 may be alternately stacked withdielectric layers therebetween.

Although the specific shape of the body 110 is not particularly limited,as illustrated, the body 110 may have a hexahedral shape or the like.Due to shrinkage of ceramic powder contained in the body 110 during afiring process, the body 110 may not have a perfectly hexahedral shapewith completely straight lines, but may have a substantially hexahedralshape overall.

The body 110 may have the first and second surfaces 1 and 2 opposingeach other in the thickness direction (the Z direction), the third andfourth surfaces 3 and 4 connected to the first and second surfaces 1 and2 and opposing each other in the longitudinal direction (the Xdirection), and the fifth and sixth surfaces 5 and 6 connected to thefirst and second surfaces 1 and 2, connected to the third and fourthsurfaces 3 and 4, and opposing each other in the width direction (the Ydirection).

A plurality of dielectric layers 111 forming the body 110 may be in afired state, and a boundary between adjacent dielectric layers 111 maybe integrated to such an extent that it is difficult to identify theindividual layers without using a scanning electron microscope (SEM).

Referring to FIG. 5 , each dielectric layer 111 may include a pluralityof dielectric grains 10 a, 10 b, and 10 c, and at least one of theplurality of dielectric grains may be a dielectric grain 10 a having acore-dual shell structure.

Referring to FIG. 6 , the dielectric grain 10 a having the core-dualshell structure may include a first shell S1 surrounding at least aportion of a core C, and a second shell S2 surrounding at least aportion of the first shell S1.

Development of multilayer ceramic capacitors (MLCC), as an example of acommon ceramic electronic component, has focused on increasing capacityand ultra-thinning of layers of MLCCs. With the increase in capacity andthe ultra-thinning in layers, it has become increasing difficult tosecure resistance to voltage characteristics of a dielectric layer inthe multilayer ceramic capacitor, and an increase in a defect rate dueto deterioration of insulation resistance of dielectric layer hasemerged as a problem.

In order to solve the problems, a method in which a rare earth elementsuch as Dy, Y, Ho, or the like is added to suppress the generation ofoxygen vacancies, to reduce mobility of the oxygen vacancies, and toremove electrons generated by the addition of a transition metal, hasbeen proposed.

However, when layers in the multilayer ceramic capacitor are thinned tohave a relatively high capacity or when a relatively high voltage isused therein under more severe use environments, there have been casesin which a simple addition of the rare earth element or the transitionelement may not sufficiently solve the above problems, or a hightemperature lifespan characteristics or a temperature coefficient ofcapacitance (TCC) characteristic depending on a change in temperaturemay not have a desirable level.

Therefore, in the present disclosure, at least one of the plurality ofdielectric grains has a core-dual shell structure, and in the core-dualshell structure, a ratio of a concentration of a rare earth elementincluded in the first shell and a concentration of a rare earth elementincluded in the second shell may be controlled to secure better hightemperature lifespan characteristics and TCC characteristics.

The rare earth elements included in the first shell S1 and the secondshell S2 may basically replace an A site or a B site of a perovskitestructure, represented by ABO₃, to form a shell region. The shell regionmay act as a barrier to prevent flow of electrons at grain boundaries ofdielectric grains, to prevent the leakage current.

In addition, as the shells S1 and S2 have a dual structure composed ofthe first shell S1 and the second shell S2 having differentconcentrations, the high temperature lifespan characteristics and theTCC characteristics may be further improved.

The rare earth element may not exist or be present in the core C, oronly a trace amount thereof may exist or be present in the core C.Therefore, a concentration of the rare earth element included in thecore C may be 0.1 times or less a concentration of the rare earthelement included in the first shell S1.

In addition, since the concentration of the rare earth element rapidlychanges at a boundary between the core C and the first shell S1, andrapidly changes at a boundary between the first shell S1 and the secondshell S2, the core C, the first shell S1, and the second shell S2 may beeasily distinguished, and may be confirmed through TEM-EDS analysis.

As illustrated in FIGS. 5 and 6 , the first shell S1 may be disposed tocover an entire surface of the core C, and the second shell S2 may bedisposed to cover an entire surface of the first shell S1. The firstshell may not cover a portion of a surface of the core (e.g., the firstshell may cover less than an entirety of the surface of the core), andthe second shell may exist in a form not covering a portion of a surfaceof the first shell (e.g., the second shell may cover less than anentirety of the surface of the first shell).

In this case, the first shell S1 may be disposed to cover at least 90area % of the surface of the core, and the second shell S2 may bedisposed to cover at least 90 area % of the surface of the first shellS1. When the first shell S1 is disposed to cover less than 90 area % ofthe surface of the core, and/or the second shell S2 is disposed to coverless than 90 area % of the surface of the first shell S1, the effect ofimproving reliability according to the present disclosure may not besufficient.

The concentration of the rare earth element included in the second shellS2 may be greater than 1.3 times and less than 3.8 times theconcentration of the rare earth element included in the first shell S1.

When the concentration of the rare earth element included in the secondshell S2 is 1.3 times or less than the concentration of the rare earthelement included in the first shell S1, the concentration of the rareearth element included in the first shell S1 may be similar to theconcentration of the rare earth element included in the second shell S2.Therefore, the effect of improving reliability according to thecore-dual shell structure may not be sufficient.

When the concentration of the rare earth element included in the secondshell S2 is 3.8 times or more than the concentration of the rare earthelement included in the first shell S1, the concentration of the rareearth element included in the second shell S2 may become too high.Therefore, since a secondary phase may be formed by the rare earthelement, reliability may be deteriorated.

Referring to FIG. 6 , a distance (LS2) corresponding to a thickness ofthe second shell along a straight line connecting α and β may be greaterthan 4% and less than 25% of a distance between α and β, where α denotesa center of the core-dual shell structure in the cross-section of thecore-dual shell structure, and β denotes a point on a surface of thesecond shell, farthest from α. In this case, α may refer to a center ofgravity of the dielectric grain in a cross-section.

When the distance (LS2) corresponding to the thickness of the secondshell along the straight line connecting α and β is 4% or less, theeffect of improving reliability may not be sufficient, and the effect ofimproving high temperature lifespan characteristics and the dielectricconstant may be deteriorated.

When the distance (LS2) corresponding to the thickness of the secondshell along the straight line connecting α and β is 25% or more, thehigh temperature lifespan characteristics may be deteriorated or thetemperature coefficient of capacitance (TCC) characteristics dependingon a change in temperature may be deteriorated.

Therefore, it is preferable that the distance (LS2) corresponding to thethickness of the second shell along the straight line connecting α and βis more than 4% and less than 25%, more preferably 4.5% or more and 24%or less, even more preferably 5% or more and 20% or less.

In this case, a distance (LS1) corresponding to the thickness of thefirst shell along the straight line connecting α and β may be 5% or moreand 30% or less of the distance between α and β.

When the distance (LS1) corresponding to the thickness of the firstshell along the straight lines connecting α and β is less than 5%, itmay be difficult to implement a dual shell structure. When the distance(LS1) corresponding to the thickness of the first shell along thestraight lines connecting α and β exceeds 30%, it may be difficult tosecure reliability.

In addition, when the distance/thickness (LS1) of the first shell isquite different from the distance of the second shell, it may bedifficult to simultaneously improve the high temperature lifespancharacteristics and the TCC characteristics. Therefore, thedistance/thickness (LS1) corresponding to the first shell among thestraight lines connecting α and β may be 0.5 to 1.5 times thedistance/thickness (LS2) corresponding to the second shell among thestraight lines connecting α and β.

Referring to FIG. 5 , the dielectric layer 111 may include a dielectricgrain 10 b having a core-shell structure, in addition to the dielectricgrain 10 a having the core-dual shell structure. Therefore, at least oneor more of the plurality of dielectric grains may be the dielectricgrain 10 b having the core-shell structure. The dielectric grain 10 bhaving the core-shell structure may include a core 10 b 1, and a shell10 b 2 surrounding at least a portion of the core 10 b 1. In this case,the shell 10 b 2 of the core-shell structure may have an amount of arare earth, different from amounts of the shells S1 and S2 of thecore-dual shell structure. The present disclosure is not limitedthereto, and the shell 10 b 2 of the core-shell structure may have thesame amount of a rare earth as an amount of one of the shells S1 and S2of the core-dual shell structure.

In addition, the dielectric layer 111 may include a dielectric grain 10c having no separate shell.

In this case, the number of the dielectric grains 10 a having thecore-dual shell structure, among the plurality of dielectric grains 10a, 10 b, and 10 c, may be 50% or more. In this case, a ratio of thenumber of dielectric grains having a core-dual shell structure may bemeasured in an image of a cross-section of the dielectric layer scannedby a transmission electron microscope (TEM).

When the number of the dielectric grains having the core-dual shellstructure, among the plurality of dielectric grains, is less than 50%,the effect of improving high temperature lifespan characteristics andthe TCC characteristic may be not sufficient.

Meanwhile, the dielectric layer 111 may include a material having aperovskite structure represented by ABO₃ as a main component.

For example, the dielectric layer 111 may include one or more of BaTiO₃,(Ba, Ca) (Ti, Ca) O₃, (Ba, Ca) (Ti, Zr) O₃, Ba (Ti, Zr) O₃, and (Ba, Ca)(Ti, Sn) O₃ as a main component.

More specifically, for example, the dielectric layer 111 may include oneor more selected from the group consisting of BaTiO₃, (Ba_(1-x)Ca_(x))(Ti_(1-y)Ca_(y)) O₃ (where 0≤x≤0.3, 0≤y≤0.1), (Ba_(1-x)Ca_(x))(Ti_(1-y)Zr_(y)) O₃ (where 0≤x≤0.3, 0≤y≤0.5), Ba (Ti_(1-y)Zr_(y)) O₃(where 0<y≤0.5), and (Ba_(1-x)Ca_(x)) (Ti_(1-y)Sn_(y))O₃ (where 0≤x≤0.3,0≤y≤0.1), as main components.

In addition, the dielectric layer 111 may include an amount of the rareearth element in a range of 0.1 to 15 moles, relative to 100 moles ofthe main component.

When an amount of the rare earth element included in the dielectriclayer 111 is less than 0.1 mole, relative to 100 moles of the maincomponent, it may be difficult to implement a core-dual shell structure.When an amount of the rare earth element included in the dielectriclayer 111 exceeds 15 moles, relative to 100 moles of the main component,the firing temperature may be rapidly increased. Therefore, it may bedifficult to obtain a dense microstructure.

In this case, the rare earth element may be one or more of lanthanum(La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr),neodium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium(Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium(Tm), ytterbium (Yb), and ruthenium (Ru).

In addition, the minor component included in the dielectric layer 111 isnot particularly limited, except that a rare earth element should beincluded, and an appropriate element and amount thereof may bedetermined to obtain desired characteristics. For example, thedielectric layer 111 may further include one or more of Mn, Cr, Ba, Si,Al, Mg, and Zr as a minor component, in addition to the rare earthelement.

A size of the dielectric grains is not particularly limited. Forexample, an average grain size of the dielectric grains in thedielectric layer 111 may be 50 nm or more and 500 nm or less.

When the average grain size is less than 50 nm, there may be a problemin that an expected effect due to a low dielectric constant and a graingrowth rate may be insufficient to achieve the expected effect. When theaverage grain size exceeds 500 nm, a change in capacity depending on atemperature and a DC voltage may increase, and reliability may decreasedue to a decrease in the number of dielectric grains per unit volume ofdielectric layer.

The body 110 may include a capacitance formation portion A disposed inthe body 110 and including a first internal electrode 121 and a secondinternal electrode 122 arranged to face and overlap each other with thedielectric layer 111 interposed therebetween, to form capacitance; andcover portions 112 and 113 formed on and below the capacitance formationportion A.

In addition, the capacitance formation portion A may be a portioncontributing to capacitance formation of a capacitor, and may be formedby repeatedly and alternately stacking the plurality of first and secondinternal electrodes 121 and 122 with dielectric layers 111 interposedtherebetween.

An upper cover portion 112 and a lower cover portion 113 may be formedby stacking a single dielectric layer or two or more dielectric layerson upper and lower surfaces of the capacitance formation portion in thevertical direction, respectively, and may function to basically preventthe internal electrodes from being damaged by external physical orchemical stress.

The upper cover portion 112 and the lower cover portion 113 may notinclude internal electrodes, and may include the same material as thedielectric layer 111.

For example, the upper cover portion 112 and the lower cover portion 113may include a ceramic material, for example, may include a bariumtitanate (BaTiO₃)-based ceramic material.

In addition, margin portions 114 and 115 may be disposed on sidesurfaces of the capacitance formation portion A.

The margin portions 114 and 115 may include a margin portion 114disposed on the sixth surface 6 of the body 110, and a margin portion115 disposed on the fifth surface 5 of the body 110. For example, themargin portions 114 and 115 may be disposed on both side surfaces of thebody 110 opposing each other in the width direction.

As illustrated in FIG. 3 , the margin portions 114 and 115 may refer toa region between ends of the first and second internal electrodes 121and 122, in the cross-section of the body 110 cut in width-thickness(WT) directions, and a boundary surface of the body 110.

The margin portions 114 and 115 may basically serve to prevent damage tothe internal electrode due to external physical or chemical stress.

The margin portions 114 and 115 may be formed by applying a conductivepaste to form internal electrodes in regions of a ceramic green sheetexcept for an edge region in which the margin portions are formed.

Alternatively or additionally, in order to suppress a step differencecaused by the internal electrodes 121 and 122, after a stackingoperation, the internal electrodes may be cut to be exposed from thefifth and sixth surfaces 5 and 6 of the body. Then, a single dielectriclayer or two or more dielectric layers may be stacked on both exposedsurfaces of the capacitance formation portion A in the width direction,to form the margin portions 114 and 115.

The internal electrodes 121 and 122 may be alternately stacked with thedielectric layer 111.

The internal electrodes 121 and 122 may include first internalelectrode(s) 121 and second internal electrode(s) 122. The first andsecond internal electrodes 121 and 122 may be alternately arranged toface and overlap each other, with the dielectric layers 111,constituting the body 110, interposed therebetween, and may respectivelybe exposed from the third and fourth surfaces 3 and 4 of the body 110.

Referring to FIG. 2 , the first internal electrode(s) 121 may beconfigured to be spaced apart from the fourth surface 4, and be exposedfrom the third surface 3, and the second internal electrode (s) 122 maybe configured to be spaced apart from the third surface 3, and beexposed from the fourth surface 4.

In this case, the first and second internal electrodes 121 and 122 maybe electrically separated from each other by the dielectric layer 111interposed therebetween.

Referring to FIG. 3 , the body 110 may be formed by alternately stackinga ceramic green sheet on which the first internal electrode 121 isprinted and a ceramic green sheet on which the second internal electrode122 is printed, and then firing the stacked ceramic green sheetlaminate.

A material for forming the internal electrodes 121 and 122 is notparticularly limited, and a material having excellent electricalconductivity may be used. For example, the internal electrodes 121 and122 may be formed by printing a conductive paste for the internalelectrodes containing one or more of nickel (Ni), copper (Cu), palladium(Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W),titanium (Ti), and alloys thereof, on the ceramic green sheet.

As a printing method of the conductive paste for the internalelectrodes, a screen-printing method, a gravure printing method, or thelike may be used, but the present disclosure is not limited thereto.

In order to achieve miniaturization and high capacitance of themultilayer ceramic capacitor, thicknesses of the dielectric layer (s)and the internal electrode (s) should be thinned to increase the numberof stacked layers. Therefore, as the thicknesses of the dielectriclayer(s) and the internal electrode(s) are thinned, reliability may bedeteriorated, and characteristics, such as an insulation resistance,breakdown voltage, or the like may be deteriorated.

Therefore, as the thicknesses of the dielectric layer(s) and theinternal electrode(s) are thinned, the effect of improving reliabilityaccording to the present disclosure may increase.

In particular, when a thickness (td) of the internal electrodes 121 and122 or a thickness (td) of the dielectric layer(s) 111 is 0.41 μm orless, the effect of improving high temperature lifespan characteristicsand the TCC characteristics according to the present disclosure may beremarkable.

The thickness (te) of the internal electrodes 121 and 122 may refer toan average thickness of the first and second internal electrodes 121 and122.

The thickness (te) of the internal electrodes 121 and 122 may bemeasured by scanning an image of a cross-section in the third and firstdirections (an L-T cross-section) of the body 110 by a scanning electronmicroscope (SEM).

For example, on the basis of a reference internal electrode layer at apoint at which a center line in the longitudinal direction of the bodyand a center line in the thickness direction of the body meet, athickness (te) of the internal electrodes 121 and 122 may be determinedby defining two points to the left and two points to the right from areference center point in the reference internal electrode layer atequal intervals, measuring a thickness of each of the defined points,and obtaining an average value therefrom, for five internal electrodelayers including the reference internal electrode layer, and two upperinternal electrode layers and two lower internal electrode layers,respectively arranged on and below the reference internal electrodelayer, among the internal electrode layers extracted from an image of across-section in the third and first directions (an L-T cross-section)of the body 110, cut in a central portion of the body 110 in the widthdirection, scanned by a scanning electron microscope (SEM).

For example, since a thickness at the reference center point in thereference internal electrode layer at a point at which a center line inthe longitudinal direction of the body and a center line in thethickness direction of the body meet, and a thickness (each 500 nm) ateach of the two points to the left and right from the reference centerpoint at equal intervals, for the above five internal electrode layers,may be measured, the thickness (te) of the internal electrodes 121 and122 may be determined as an average value of the thicknesses of thetotal 25 points.

The thickness (td) of the dielectric layer 111 may refer to an averagethickness of the dielectric layer(s) 111 disposed between the first andsecond internal electrodes 121 and 122.

Similar to the thickness (te) of the internal electrode, the thickness(td) of the dielectric layer 111 may be measured by scanning an image ofa cross-section in the third and first directions (an L-T cross-section)of the body 110 by a scanning electron microscope (SEM).

For example, on the basis of a reference dielectric layer at a point atwhich a center line in the longitudinal direction of the body and acenter line in the thickness direction of the body meet, a thickness(td) of the dielectric layer 111 may be determined by defining twopoints to the left and two points to the right from a reference centerpoint in the reference dielectric layer at equal intervals, measuring athickness of each of the defined points, and obtaining an average valuetherefrom, for five dielectric layers including the reference dielectriclayer, and two upper dielectric layers and two lower dielectric layers,respectively arranged on and below the reference dielectric layer, amongthe dielectric layers extracted from an image of a cross-section in thethird and first directions (an L-T cross-section) of the body 110, cutin a central portion of the body 110 in the width direction, scanned bya scanning electron microscope (SEM).

For example, since a thickness at the reference center point in thereference dielectric layer at a point at which a center line in thelongitudinal direction of the body and a center line in the thicknessdirection of the body meet, and a thickness (each 500 nm) at each of thetwo points to the left and right from the reference center point atequal intervals, for the above five dielectric layers, may be measured,the thickness (td) of the dielectric layer 111 may be determined as anaverage value of the thicknesses of the total 25 points.

The external electrodes 131 and 132 may be arranged on the body 110, andmay be connected to the internal electrodes 121 and 122, respectively.

As illustrated in FIG. 2 , first and second external electrodes 131 and132 may be disposed on the third and fourth surfaces 3 and 4 of the body110, respectively, and may be connected to the first and second internalelectrodes 121 and 122, respectively.

In the present embodiment, a structure in which the ceramic electroniccomponent 100 has two external electrodes 131 and 132 may be described,but the number, shape, and the like of the external electrodes 131 and132 may be changed, depending on shapes of the internal electrodes 121and 122, or other purposes.

The external electrodes 131 and 132 may be formed using any material aslong as they have electrical conductivity such as metal, a specificmaterial may be determined in consideration of electricalcharacteristics, structural stability, and the like, and may have amultilayer structure.

For example, the external electrodes 131 and 132 may include electrodelayers 131 a and 132 a, and plated layers 131 b and 132 b formed on theelectrode layers 131 a and 132 a, respectively.

As a more specific example of the electrode layers 131 a and 132 a, theelectrode layers 131 a and 132 a may be sintered electrodes including aconductive metal and a glass, or resin-based electrodes including aconductive metal and a resin.

In addition, the electrode layers 131 a and 132 a may have a form inwhich the sintered electrode and the resin-based electrode aresequentially formed on the body 110. In addition, the electrode layers131 a and 132 a may be formed by transferring a sheet including theconductive metal on the body 110, or may be formed by transferring thesheet including the conductive metal on the sintered electrode.

The conductive metal used for the electrode layers 131 a and 132 a isnot particularly limited as long as it is a material that may beelectrically connected to the internal electrode(s) to form capacitance.For example, the conductive metal may be one or more of nickel (Ni),copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin(Sn), tungsten (W), titanium (Ti), and alloys thereof.

The plated layers 131 b and 132 b may be plated layers including one ormore of nickel (Ni), tin (Sn), palladium (Pd), and alloys thereof, andmay be formed of a plurality of layers.

As a more specific example of the plated layers 131 b and 132 b, theplated layers 131 b and 132 b may be nickel (Ni) plated layers or tin(Sn) plated layers, may have a form in which the nickel (Ni) platedlayers and the tin (Sn) plated layers are sequentially formed on theelectrode layers 131 a and 132 a, and may have a form in which a tin(Sn) plated layer, a nickel (Ni) plated layer, and another tin (Sn)plated layer are formed sequentially. In addition, the plated layers 131b and 132 b may include a plurality of nickel (Ni) plated layers and/ora plurality of tin (Sn) plated layers.

Method of Manufacturing Ceramic Electronic Component

Hereinafter, a method of manufacturing a ceramic electronic componentaccording to another aspect of the present disclosure will be describedin detail. However, in order to avoid overlapping descriptions,descriptions overlapping those described in the ceramic electroniccomponent will be omitted.

According to another aspect of the present disclosure, a method ofmanufacturing a ceramic electronic component, includes: preparing a basematerial powder having a core-shell structure having a core and a shell,the shell including a rare earth element; adding a minor component tothe base material powder to prepare a ceramic green sheet; printing aconductive paste for an internal electrode on the ceramic green sheet,and then stacking the printed ceramic green sheet to prepare a stackedbody; firing the stacked body to prepare a body including a dielectriclayer and an internal electrode; and forming an external electrode onthe body, wherein an amount of the rare earth element included in thebase material powder is more than 0.6 times to less than 2.4 times anamount of a rare earth element included in the minor component.

First, a base material powder having a core-shell structure having acore and a shell, the shell including a rare earth element, may beprepared.

When the base material powder does not have the core-shell structure, itmay be difficult to implement dielectric grains having a core-dual shellstructure according to the present disclosure.

The method of manufacturing the base material powder having thecore-shell structure is not specifically limited. For example, whenmanufacturing BaTiO₃ by a hydrothermal synthesis process, the rare earthelement may be added, in the process of growing the powder to a desiredsize, to synthesize the base material powder. Alternatively, aftermixing the BaTiO₃ with the rare earth element, the base material powderhaving the core-shell structure may be manufactured through heattreatment.

Next, a minor component may be added to the base material powder toprepare a ceramic green sheet. In this case, after adding the minorcomponent to the base material powder, ethanol and toluene as a solventmay be mixed with a dispersant, and a binder may be further mixedtherewith to produce a ceramic sheet.

In order to implement dielectric grains having a core-dual shellstructure according to the present disclosure, an amount of the rareearth element included in the base material powder may be controlled tobe more than 0.6 times to less than 2.4 times an amount of a rare earthelement included in the minor component.

When an amount of the rare earth element included in the base materialpowder is 0.6 times or less an amount of the rare earth element includedin the minor component, the dielectric properties may be deteriorated.When an amount of the rare earth element included in the base materialpowder is 2.4 times or more an amount of the rare earth element includedin the minor component, it may be difficult to implement dielectricgrains having a core-dual shell structure according to the presentdisclosure.

Therefore, an amount of the rare earth element included in the basematerial powder is preferably more than 0.6 times and less than 2.4times, more preferably 0.7 times or more and 2.2 times or less, evenmore preferably 0.8 times or more and 2.0 times or less an amount of therare earth element included in the minor component.

In addition, the element included in the minor component, except for therare earth element, is not specifically limited, and may be suitablycontrolled to acquire desired characteristics.

Next, after printing an electrically conductive paste for internalelectrodes on the ceramic sheet, a plurality of printed ceramic sheetsmay be stacked to prepare a stacked body.

Next, the stacked body may be fired to prepare a body includingdielectric layer(s) and internal electrode(s).

In this case, the dielectric layer(s) may include a plurality ofdielectric grains, at least one or more of the plurality of dielectricgrains may have a core-dual shell structure having a core and a dualshell, the dual shell may include a first shell surrounding at least aportion of the core, and a second shell surrounding at least a portionof the first shell, and a concentration of a rare earth element includedin the second shell may be more than 1.3 times to less than 3.8 times aconcentration of a rare earth element included in the first shell.

In addition, in order to make a concentration of a rare earth elementincluded in the second shell be more than 1.3 times and less than 3.8times a concentration of a rare earth element included in the firstshell, a firing temperature as well as an amount of a rare earthelement, which are added to the base material powder and the minorcomponent, are adjusted suitably.

A specific numerical range of the firing temperature may vary dependingon a type and amount of additional elements, but is not particularlylimited. For example, the range of the firing temperature may be morethan 1230° C. and less than 1280° C.

Next, an external electrode may be formed on the body to obtain aceramic electronic component.

Example

The base material powders illustrated in Table 1 below were prepared. Inthis case, “1.2Dy doped BT” refers to a base material powder that has acore-shell structure having a core and a shell and containing 1.2 mol ofDy in the shell, compared to 100 moles of BaTiO₃. In addition, “0.5Dydoped BT” refers to a base material powder having a core-shell structurehaving a core and a shell and containing 0.5 mol of Dy in the shell,compared to 100 moles of BaTiO₃. In addition, “Non doped BT” refers to aBaTiO₃ powder having no core-shell structure.

Thereafter, the base material powder was added with the minor componentslisted in Table 1 below, mixed with a dispersant using ethanol andtoluene as a solvent, and then a binder was further mixed, to prepare aceramic sheet. An Ni electrode was printed on the prepared ceramicsheet, and a plurality of printed ceramic sheets were stacked, pressed,and cut to prepare a plurality of chips. The chips were calcined forremoving the binder, and then a firing operation under a reducingatmosphere was performed at the firing temperatures illustrated in Table1 below, to prepare sample chips.

Dielectric constants, 125° C. TCC values, and high temperature lifespancharacteristics of the prepared sample chips were measured and arereported in Table 2 below.

The 125° C. TCC values were measured using a LCR meter at a temperaturerange of −55° C. to 125° C. at 1 kHz and 1 V.

Tests for the high temperature lifespan characteristics (hightemperature IR boosting tests) were performed by maintaining conditionsincluding 150° C. and 1 Vr=10 V/μm for 40 samples for each test numberfor 30 minutes, increasing the voltages in times, and calculating anaveraged value of the voltage value. In this case, “1 Vr” refers to 1reference voltage, and “10 V/μm” refers to a voltage of 10 V per 1 μm ofthickness of a dielectric.

In addition, cross-sections of the sample chips in longitudinal andthickness directions (L-T cross-sections), cut in a central portion ofeach of the sample chips in the width direction, were analyzed by atransmission electron microscope (TEM) and an energy dispersive X-rayspectroscopy (EDS) apparatus to illustrate concentrations*, lengths*,and fractions* in Table 2 below. 200 kV ARM was used as the TEM, and wasmeasured with spot 4, 100,000 times. STEM-EDS was measured with 100points at 10 nm intervals.

The concentrations* were determined by performing an energy dispersiveX-ray spectroscopy (EDS) line analysis installed on a transmissionelectron microscope (TEM) for grains having the core-dual shellstructure, and dividing a value subtracted Dy intensity of a core fromDy intensity of a second shell, by a value subtracted Dy intensity ofthe core from Dy intensity of a first shell.

The lengths* were determined by performing a TEM EDS line analysis forthe grains having the core-dual shell structure as illustrated in FIG. 7, and illustrating results of [the number of points measured in theLS2]/[the total number of points measured from α to β].

The fractions* were determined by measuring ratios of the number ofgrains having a core-dual shell structure relative to the total numberof dielectric grains in the 10 μm×10 μm regions, central portions of thecross-sections in the longitudinal and thickness directions (L-Tcross-sections).

TABLE 1 Test Base Material Minor Components Firing Nos. Powders (Molesrelative to 100 moles of Base Material Powders) Temp. (° C.)  1* 1.2Dydoped BT Dy 1.3, Mn 0.05, Cr 0.2, Ba 2.4, Si 2.0, Al 1.0, 1230 Mg 0.4,Zr 0.4 2 Dy 1.3, Mn 0.05, Cr 0.2, Ba 2.4, Si 2.0, Al 1.0, 1250 Mg 0.4,Zr 0.4 3 Dy 1.3, Mn 0.05, Cr 0.2, Ba 2.4, Si 2.0, Al 1.0, 1260 Mg 0.4,Zr 0.4  4* Dy 1.3, Mn 0.05, Cr 0.2, Ba 2.4, Si 2.0, Al 1.0, 1280 Mg 0.4,Zr 0.4  5* Dy 0.5, Mn 0.05, Cr 0.2, Ba 2.4, Si 2.0, Al 1.0, 1260 Mg 0.4,Zr 0.4  6* Dy 2.0, Mn 0.05, Cr 0.2, Ba 2.4, Si 2.0, Al 1.0, 1260 Mg 0.4,Zr 0.4  7* 0.5Dy doped BT Dy 0.5, Mn 0.2, Ba 2.0, Si 2.0, Al 0.5 Mg 1.0,Zr 0.3 1210 8 Dy 0.5, Mn 0.2, Ba 2.0, Si 2.0, Al 0.5 Mg 1.0, Zr 0.3 12409 Dy 0.5, Mn 0.2, Ba 2.0, Si 2.0, Al 0.5 Mg 1.0, Zr 0.3 1250 10* Dy 0.5,Mn 0.2, Ba 2.0, Si 2.0, Al 0.5 Mg 1.0, Zr 0.3 1280 11* Non doped BT Dy2.5, Mn 0.05, Cr 0.2, Ba 2.4, Si 2.0, Al 1.0, 1250 Mg 0.4, Zr 0.4 12* Dy1.0, Mn 0.2, Ba 2.0, Si 2.0, Al 0.5 Mg 1.0, Zr 0.3 1230

TABLE 2 Test Dielectric High Temp. Lifespan Nos. Constants 125° C. TCCCharacteristics(V/μm) Concentrations* Lengths* Fractions* Examples  1*2600  −6% 33 5.2  4/100 36% Comparative 2 2600  −8% 72 2.8  5/100 65%Inventive 3 2700  −8% 81 3.0 10/100 63% Inventive  4* 3200 −17% 44 1.328/100 56% Comparative  5* 3000 −14% 31 0.4 25/100 59% Comparative  6*2400  −4% 26 7.3  5/100 63% Comparative  7* 2500  −8% 38 3.8  4/100 32%Comparative 8 2800 −10% 76 1.5 18/100 68% Inventive 9 3000 −15% 81 1.520/100 72% Inventive 10* 2900 −14% 54 1.1 15/100 62% Comparative 11*2800 −10% 48 — — — Comparative 12* 2900 −12% 44 — — — Comparative

Test Nos. 2, 3, 8, and 9 were confirmed that concentrations of the rareearth elements included in the second shells satisfy 1.3 times or moreand less than 3.8 times concentrations of the rare earth elementsincluded in the first shells, to provide excellent reliability for hightemperature lifespan characteristics. In addition, Test Nos. 2, 3, 8,and 9 were confirmed that dielectric constants and 125° C.characteristics therefor are excellent.

Test Nos. 11 and 12, which do not include grains having a core-dualshell structure, were inferior in reliability for high temperaturelifespan characteristics.

In addition, Test Nos. 1, 5 to 7, and 10, which include grains having acore-dual shell structure, but concentrations of the rare earth elementsincluded in the second shell are 1.3 times or less or 2.8 times or morethan concentrations of the rare earth elements included in the firstshell, were inferior in reliability for high temperature lifespancharacteristics.

In particular, Test Nos. 1 and 4 were confirmed to be inferior inreliability for high temperature lifespan characteristics, relative toTest No. 11 having the same composition and no core-dual shellstructure, and Test No. 7 was confirmed to be inferior in reliabilityfor high temperature lifespan characteristics, relative to Test No. 12having the same composition and no core-dual shell structure. Therefore,it may be seen that the reliability for high temperature lifespancharacteristics may be remarkably improved by controlling aconcentration of a rare earth element included in the second shell tosatisfy more than 1.3 times and less than 3.8 times a concentration of arare earth element included in the first shell.

FIG. 7 illustrates intensities of Dy measured as results of XRF EDS lineanalysis for grains having a core-dual shell structure of Test No. 9, anInventive Example.

In FIG. 7 , intensity of Dy in a distance (LC) corresponding to a coreis about 25 on average, which indicates that Dy is not present therein.The intensity of Dy in the distance (LC) corresponding to the core mayvary, depending on TEM facility and measurement condition environments,but a portion having the lowest value of measured intensity may beregarded as the core, and there may be no Dy in the core.

Intensity of Dy in a distance (LS1) corresponding to a first shell isabout 51 on average, and intensity of Dy in a distance (LS2)corresponding to a second shell is about 64 on average. Therefore, sincea value subtracted Dy intensity of the core from Dy intensity of thesecond shell is 1.5 times a value subtracted Dy intensity of the corefrom Dy intensity of the first shell, a concentration of the rare earthelement included in the second shell is 1.5 times a concentration of therare earth element included in the first shell. Intensity of Dy in adistance (LS1) corresponding to the first shell and intensity of Dy in adistance (LS2) corresponding to the second shell may also vary,depending on TEM facility and measurement condition environments, but aratio of concentrations of the rare earth elements between the firstshell and the second shell may be maintained.

According to an aspect of the present disclosure, a ceramic electroniccomponent includes a body including a dielectric layer and an internalelectrode; and an external electrode disposed on the body and connectedto the internal electrode, wherein the dielectric layer includes aplurality of dielectric grains, wherein at least one of the plurality ofdielectric grains has a core-dual shell structure having a core and adual shell, wherein the dual shell has a first shell surrounding atleast a portion of the core, and a second shell surrounding at least aportion of the first shell, wherein a concentration of a rare earthelement included in the second shell is more than 1.3 times to less than3.8 times a concentration of a rare earth element included in the firstshell.

According to another aspect of the present disclosure, a method ofmanufacturing a ceramic electronic component includes preparing a basematerial powder having a core-shell structure having a core and a shell,the shell including a rare earth element; adding a minor component tothe base material powder to prepare a ceramic green sheet; printing aconductive paste for an internal electrode on the ceramic green sheet,and then stacking the printed ceramic green sheet to prepare a stackedbody; firing the stacked body to prepare a body including a dielectriclayer and an internal electrode; and forming an external electrode onthe body, wherein an amount of the rare earth element included in thebase material powder is more than 0.6 times to less than 2.4 times anamount of a rare earth element included in the minor component.

While embodiments have been illustrated and described above, it will beapparent to those skilled in the art that modifications and variationscould be made without departing from the scope of the present disclosureas defined by the appended claims.

What is claimed is:
 1. A ceramic electronic component comprising: a bodyincluding a dielectric layer and an internal electrode; and an externalelectrode disposed on the body and connected to the internal electrode,wherein the dielectric layer comprises a plurality of dielectric grains,wherein at least one of the plurality of dielectric grains has acore-dual shell structure having a core and a dual shell, wherein thedual shell comprises a first shell surrounding at least a portion of thecore, and a second shell surrounding at least a portion of the firstshell, and wherein a concentration of a rare earth element included inthe second shell is more than 1.3 times to less than 3.8 times aconcentration of a rare earth element included in the first shell. 2.The ceramic electronic component according to claim 1, wherein athickness of the second shell along a straight line connecting α and βis greater than 4% and less than 25% of a distance between α and β,where α denotes a center of the core-dual shell structure in across-section of the core-dual shell structure, and β denotes a pointfarthest from α on a surface of the second shell.
 3. The ceramicelectronic component according to claim 2, wherein a thickness of thefirst shell along the straight line connecting α and β is 5 to 30% ofthe distance between α and β.
 4. The ceramic electronic componentaccording to claim 2, wherein a thickness of the first shell along thestraight line connecting α and β is 0.5 to 1.5 times the thickness ofthe second shell along the straight line connecting α and β.
 5. Theceramic electronic component according to claim 1, wherein aconcentration of any rare earth element included in the core of thecore-dual shell structure is 0.1 times or less than the concentration ofthe any rare earth element included in the first shell.
 6. The ceramicelectronic component according to claim 1, wherein the first shell inthe core-dual shell structure is disposed to cover at least 90 area % ofa surface of the core, and the second shell in the core-dual shellstructure is disposed to cover at least 90 area % of a surface of thefirst shell.
 7. The ceramic electronic component according to claim 1,wherein at least one of the plurality of dielectric grains has acore-shell structure.
 8. The ceramic electronic component according toclaim 1, wherein a total number of dielectric grains having thecore-dual shell structure in the dielectric layer is 50% or more of atotal number of the plurality of dielectric grains in the dielectriclayer.
 9. The ceramic electronic component according to claim 1, whereinthe dielectric layer comprises one or more of BaTiO₃, (Ba,Ca)(Ti,Ca)O₃,(Ba,Ca)(Ti,Zr)O₃, Ba(Ti,Zr)O₃, and (Ba,Ca)(Ti,Sn)O₃ as a main component.10. The ceramic electronic component according to claim 9, wherein thedielectric layer has an amount of the rare earth element in a range of0.1 to 15 moles, relative to 100 moles of the main component.
 11. Theceramic electronic component according to claim 1, wherein the rareearth element is one or more of lanthanum (La), yttrium (Y), actinium(Ac), cerium (Ce), praseodymium (Pr), neodium (Nd), promethium (Pm),samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium(Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), andruthenium (Ru).
 12. The ceramic electronic component according to claim9, wherein the dielectric layer further comprises one or more of Mn, Cr,Ba, Si, Al, Mg, and Zr as a minor component.
 13. A method ofmanufacturing the ceramic electronic component of claim 1, comprising:preparing ceramic green sheets each including a base material powder anda minor component added to the base material powder, the base materialpowder having a core-shell structure having a core and a shell, and theshell including a rare earth element; printing a conductive paste for aninternal electrode on the ceramic green sheets, and stacking the printedceramic green sheets to prepare a stacked body; firing the stacked bodyto prepare a body including a dielectric layer and an internalelectrode; and forming an external electrode on the body, wherein anamount of the rare earth element included in the base material powder ismore than 0.6 times to less than 2.4 times an amount of a rare earthelement included in the minor component.
 14. The method according toclaim 13, wherein the dielectric layer comprises a plurality ofdielectric grains, wherein at least one or more of the plurality ofdielectric grains has a core-dual shell structure having a core and adual shell, wherein the dual shell comprises a first shell surroundingat least a portion of the core of the core-dual shell structure, and asecond shell surrounding at least a portion of the first shell, whereina concentration of a rare earth element included in the second shell ismore than 1.3 times to less than 3.8 times the concentration of a rareearth element included in the first shell.
 15. The method according toclaim 14, wherein a thickness of the second shell along a straight lineconnecting α and β is greater than 4% and less than 25% of a distancebetween α and β, where α denotes a center of the core-dual shellstructure in a cross-section of the core-dual shell structure, and βdenotes a point farthest from α on a surface of the second shell. 16.The method according to claim 14, wherein a total number of dielectricgrains having the core-dual shell structure in the dielectric layer is50% or more of a total number of the plurality of dielectric grains inthe dielectric layer.
 17. The method according to claim 14, wherein thefiring is performed at a firing temperature such that the concentrationof the rare earth element included in the second shell is more than 1.3times to less than 3.8 times of the concentration of the rare earthelement included in the first shell.
 18. The method according to claim13, wherein the firing operation is carried out in a firing temperaturerange of more than 1230° C. to less than 1280° C.
 19. A ceramicelectronic component comprising: a body including first and secondinternal electrodes overlapping each other with a dielectric layerdisposed therebetween, wherein, in a region of the dielectric layerdisposed 0.41 μm or less from both the first and second internalelectrodes, 50% or more of a total number of dielectric grains in thedielectric layer have a core-dual shell structure having a core, a firstshell having a composition different from the core and surrounding atleast a portion of the core, and a second shell having a compositiondifferent from the first shell and surrounding at least a portion of thefirst shell.
 20. The ceramic electronic component of claim 19, whereineach of the first and second shells include a rare earth element in aconcentration higher than the core.
 21. The ceramic electronic componentof claim 19, wherein a concentration of a rare earth element included inthe second shell is more than 1.3 times to less than 3.8 times aconcentration of a rare earth element included in the first shell. 22.The ceramic electronic component of claim 19, wherein a thickness of thesecond shell along a straight line connecting α and β is greater than 4%and less than 25% of a distance between α and β, where α denotes acenter of the core-dual shell structure in a cross-section of thecore-dual shell structure, and β denotes a point farthest from α on asurface of the second shell.
 23. The ceramic electronic component ofclaim 19, wherein the dielectric layer has an amount of the rare earthelement in a range of 0.1 to 15 moles, relative to 100 moles of a maincomponent including one or more of BaTiO₃, (Ba,Ca)(Ti,Ca)O₃,(Ba,Ca)(Ti,Zr)O₃, Ba(Ti,Zr)O₃, and (Ba,Ca)(Ti,Sn)O₃.
 24. A ceramicelectronic component comprising: a body including first and secondinternal electrodes overlapping each other with a dielectric layerdisposed therebetween, wherein, in a region of the dielectric layerdisposed 0.41 μm or less from both the first and second internalelectrodes, dielectric grains of the dielectric layer have core-shellstructures having a core and a first shell surrounding at least aportion of the core and including a rare earth element in aconcentration higher than the core, the dielectric grains of thedielectric layer have core-dual shell structures further including asecond shell having a composition different from the first shell, andthe second shell includes a rare earth element in a concentration higherthan the first shell.
 25. The ceramic electronic component of claim 24,wherein the concentration of the rare earth element included in thesecond shell is more than 1.3 times to less than 3.8 times theconcentration of the rare earth element included in the first shell. 26.The ceramic electronic component of claim 24, wherein a thickness of thesecond shell along a straight line connecting α and β is greater than 4%and less than 25% of a distance between α and β, where α denotes acenter of the core-dual shell structure in a cross-section of thecore-dual shell structure, and β denotes a point farthest from α on asurface of the second shell.